A common fluid treatment apparatus generally uses one or more treatment mediums to perform treatment on various fluids, such as water, ethanol, and the like. When a fluid passes through treatment mediums accommodated in the fluid treatment device, the impurities, pollutant and some components contained therein are removed by physical reaction or chemical reaction with the treatment mediums via contacting therewith. Now, a shower filter, serving as an example of the fluid treatment device, is taken as an example to make explanations.
Referring to FIG. 1, for example, an electric shower heater 901 is generally connected after a shower filter 902 so as to perform treatments, such as chlorine removal, on the water before being supplied to the electric shower heater 901.
In a general design of the fluid treatment device, the fluid passing through the treatment mediums flows, during service, in a direction which tends to compact the treatment mediums. Thus, any dirt or other impurities which are removed by the treatment mediums will be adsorbed in the treatment mediums and accumulate to eventually clog the treatment mediums or deteriorate their treatment performance. Once this situation occurs, the service life of the treatment mediums will be ended and the treatment mediums need to be replaced with new treatment mediums. Thus, the service life of the treatment mediums is short and the usage amount thereof is large.
As the treatment mediums are compacted during service, the resistance to which the incoming water flowing through the treatment mediums is subjected is increased, there is loss in water pressure, and the output water flow decreases. Especially before the treatment mediums having been used for a period of time but having not been replaced, the treatment mediums that adsorb a large amount of dirt will further increase the resistance, the pressure loss increases, and the output water flow decreases. In addition, the dirt contained in the top-down incoming water may be captured on a top of the treatment medium bed which will blind off the medium bed, resulting in huge pressure loss and significant decreasing of the water flow (the water pressure needs to be increased if the same water flow as before needs to be achieved). This case is more prominent in regions with a low water pressure. For example, in Brazil and other regions, many users receive their shower water from a tank that is located on a top of the building. In such a case, a top apartment of the building may only have a head pressure of 1.5 meters (a height of water above the shower pipe). One can imagine in the case of 1.5 meters of water pressure, plus with the resistance imposed by the treatment mediums in the shower filter with dirt gathered therein, the output water flow may be as small as the extent to which a normal shower cannot be performed.
In addition, a minimum water flow as required for use of the shower is 3 liters per minute. In regions with a low water pressure, such as Brazil, the shower filter with the above general fluid treatment design is only able to deal with 4 liters per minute at 4 meters of water pressure at the beginning, the amount of water to be dealt with is small, which is not conducive to use of the shower.
In addition, a United State patent application with a publication No. U.S. Pat. No. 5,503,742 discloses assembly of a shower filter. Referring to FIG. 2, the assembly of shower filter has two separate housing members 903, 904 which are easily taken apart. After being used for a period of time, an internal filter element 905 can be taken out, and reinserted into the housing members 903, 904 after being reversed to perform a backwash operation, so as to prevent the shower filter from being clogged and limiting the flow of water there through. However, such a backwash operation is not only very cumbersome, but also is not effective, because the dirt and impurities that are bonded on the surface of the treatment mediums are not easy to be removed through such a simple backwash operation.